Many years ago when I was a non-tenure-track professor, I was taken aback when I learned that the quality of teaching by people in my position -- that is, all non-tenure track instructors -- was considered a priori sub-standard by my institution because we had no long-term investment in the college.
The Dean said this aloud in a meeting and repeated it in a memo. At the meeting, I thought I misunderstood the Dean, but the memo was unambiguous. Tenure-track and tenured faculty had a commitment to the college and the rest of us didn't, so their teaching was, by definition, of higher quality than ours. I doubt if this conclusion was supported by any data; it seemed to be more a belief. I didn't see the point of stating it so explicitly, as a generalization, but of course the focus was to make the the 'real' faculty feel good.
I found that somewhat demoralizing. I cared a lot about my students and my teaching, and I was working extremely hard at my teaching, as I also had in a previous position as a non-tenure-track instructor. Some of my tenured and tenure-track colleagues were doing the same, and some weren't. I channeled my annoyance into targeted loathing of the Dean (but not the college, my colleagues, or my students), and focused on my work.
Later, when I was a tenure-track and then tenured professor at a large university, I learned that the quality of teaching by people in my position was considered by some to be a priori sub-standard because we spent so much time doing research, we couldn't be as good at teaching as those who are entirely dedicated to teaching, including non-tenure-track (adjunct/contingent) faculty. This was the view, not so much of the institution itself, but of a broader community (and in particular those focused on college-level science education).
The reason both statements could be made and thought possibly true by some is that the first one involved a small liberal arts college and the second a large research university.
These generalizations are meaningless. There are good, bad, and mediocre teachers in all the possible types of jobs involving teaching at the different types of colleges and universities in the US and beyond.
Here is my own (possibly meaningless) generalization, or belief, based on no data, just observations in the past 30 years as an undergraduate, graduate student, instructor, and the various stages of tenure-track/tenured professor:
Teaching quality (TQ) for an individual or even a group of individuals in similar jobs does not correlate with type of institution or with job title.
If that is the case, then TQ is more a function of an individual's teaching skills and dedication, both of which are somewhat fluid concepts because they can change with time and circumstance, but are still more important than institution type of job title. There may well be some 'environmental' factors such as teaching load, support from the institution etc., but it is not useful to make assumptions about whether someone will be a good, bad, or indifferent teacher based on whether that person is employed at a small college, a large research university, a private institution, a state institution etc. or whether that person is an adjunct or a senior, tenured professor. I don't think this is a controversial statement, but I am still surprised when -- to this day -- I encounter these stereotypes.
The issue that is relevant to students is whether they are likely to encounter more good teachers in certain circumstances than in others, but I am not going to wade into these larger issues, including debates about how we measure TQ, the value of student evaluations of teaching, whether students are at a disadvantage (or advantage) if taught by large number of adjunct faculty, and so on (I have discussed these in other posts),
My point today is a small one, inspired by a recent experience in which someone from the small-college world expressed surprise that teaching excellence could be found at a large university, bringing back some memories and triggering this post.